Otake, Y.

Paper	Title	Page
TOAA03	Status of the X-Ray FEL Control System at SPring-8	50
	T. Hirono, N. Hosoda, M. Ishii, T. Masuda, T. Matsushita, T. Ohata, M. T. Takeuchi, R. Tanaka, A. Yamashita JASRI/SPring-8, Hyogo-ken M. K. Kitamura, H. Maesaka, Y. Otake, K. Shirasawa RIKEN Spring-8 Harima, Hyogo T. Fukui RIKEN, Hyogo
	The X-ray FEL project at SPring-8 aims to build an X-ray lasing facility, which will generate brilliant coherent X-ray beams with wavelength of below 0.1nm. A combination of short-period in-vacuum undulators and an 8GeV high-gradient C-band linear accelerator makes the machine compact enough to fit into the SPring-8 1km-long beamline space. The machine commissioning will be started by March 2011. We designed the control system for the new machine based on the present SCSS test accelerator, which employs the MADOCA framework. The control system is based on the so-called “standard model” and composed of Linux-based operator consoles, database servers, Gigabit Ethernet, VMEbus system, and so on. The control system, also, has a synchronized data-taking scheme to achieve beam-based optics tuning. Most of the device control part is installed in water-cooled 19in. racks together with RF devices for temperature control, which guarantees stable RF phase control. This paper gives an overview of the project and describes the design of the control system. In addition, we briefly report the status of the SCSS test accelerator operated as a VUV-FEL user facility.
	Slides
FOAA02	Timing and LLRF System of Japanese XFEL to Realize Femto-Second Stability	706
	T. Fukui, N. Hosoda, H. Maesaka, T. Ohshima, T. Shintake RIKEN, Hyogo K. Imai, M. Kourogi OPtical Comb, Inc., Yokohama M. K. Kitamura, K. Tamasaku, Y. Otake RIKEN Spring-8 Harima, Hyogo M. Musya University of electro-communications, Tokyo T. Ohata JASRI/SPring-8, Hyogo-ken
	At SPring-8, the construction of a 5712-MHz linac and undulators as a light source for XFEL is in progress. There are two parts of the linac in accordance with requirements of phase accuracy to realize a stable SASE generation. One is a crest acceleration part using a sinusoidal wave. The other is an off-crest part that corresponds to a bunch compressor giving an energy chirp to a beam bunch. To generate the stable SASE, the beam energy stability of 10-4 is required. To obtain this stability, the accuracy of sub-picoseconds is required in the crest part, and several ten femto-seconds are necessary in the off-crest part. The requirement in the crest part was achieved by rf control instruments based on an electronic circuit in the SCSS prototype accelerator. However, realizing the several ten femto-seconds accuracy is almost impossible by the present electronic circuit technology. Therefore, for overcoming this fact, we employed laser technology. In this paper, we describe a system based on IQ control technology to obtain sub-picoseconds accuracy and an optical signal distribution system using an optical comb generator that could realize several ten femto-seconds accuracy.
	Slides